Heat-removal device

ABSTRACT

A heat-removal device for removing heat from a hot surface includes a housing containing a cooling fluid. The housing has a heat-absorption section, which is in contact with the hot surface. The housing also has a heat-dissipation section, which is cooled by natural or forced convection with ambient air. An internal impeller circulates the cooling fluid in a closed loop between the heat-absorption section and the heat-dissipation section to transport heat away from the hot surface to the ambient air.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Serial No. 60/920,203, filed Mar. 27, 2007

FIELD OF THE INVENTION

This invention relates to a device for efficiently removing largequantities of heat generated within a relatively small area such asElectronic Devices, Integrated Circuits, Bearings, etc.

BACKGROUND OF THE INVENTION

The problem of efficiently removing heat generated within relativelysmall areas such as Integrated Circuits, Bearings, etc. has long plaguedengineers. If generated heat is not removed efficiently from such parts,the performance or longevity of the part can be adversely affected.

A common problem is heat removal from integrated circuits (ICs). As ICsget smaller, they generate more heat within smaller volumes. If thisheat is not removed, the IC overheats causing loss of performance andmalfunction. A specific example is the common problem of reduction ofperformance of a computer due to overheating of its Central ProcessingUnit (CPU).

Typically a finned aluminum or copper block, with or without reticulatedmetallic foam, such as that described in U.S. Pat. Nos. 6,424,529,6,424,531, and others is used to transfer heat generated within anIntegrated Circuit (IC) to the external environment by natural or forcedconvection with ambient air. However such IC Coolers are relativelyinefficient at transferring the heat, especially from modern computerchips which generate tremendous amounts of heat. The overheating of thecomputer chips reduces the processing ability of the chips. Furthermore,reticulated metallic-foam is relatively expensive.

Other designs, which incorporate heat-pipes, are also used to attempt toremove the generated heat from ICs. However, they are complicated andexpensive to manufacture. U.S. Pat. No. 5,949,648 to Liao describes sucha heat-pipe design.

Other designs, which are similar to automotive radiator systems, usecirculated water and a remote heat-exchanger and cooling-fan. Thesedesigns, while able to provide good cooling, are very large, areassembled from a number of parts, and are expensive to produce.

Similarly, as rotating equipment gets miniaturized, it generates largequantities of heat from miniaturized bearings. If the heat is notremoved from these bearings, they are liable to overheat and seize. Thehigher operating temperature of these bearings reduces their operatinglife. There is therefore also a great need for a heat-removal devicethat will efficiently transfer the generated heat away from a bearing orother small machine part.

Many other mechanical, electrical and chemical devices generate largeamounts of heat in a small area and would benefit from a high efficiencyheat-removal device described in this invention.

SUMMARY OF THE INVENTION

In one aspect of the present invention a device for removing heat from ahot-surface comprises a generally closed housing, the housing having aheat-absorbing section and a heat-dissipation section, theheat-absorbing section having an external surface in contact with thehot-surface and an internal surface, the heat-dissipation section havingan external surface which is exposed to the external environment and aninternal surface and a heat-conducting fluid located within the housing,the heat-conducting fluid generally contacting both the internal surfaceof the heat-absorbing section and the internal surface of theheat-dissipation section.

In another aspect of the present invention, the Heat Removal Devicefurther includes a fluid-circulation means (FCM) for circulating theheat-conducting fluid past the internal surface of the heat-absorbingsection and the internal surface of the heat-dissipation section of thehousing.

In yet another aspect of the present invention, the Heat Removal Devicefurther includes an open fluid-flow-passage (FFP) which has a first openend submerged in the heat-conducting fluid adjacent to the internalsurface of the heat-absorbing section of the housing and a second openend submerged in the heat-conducting fluid adjacent to the internalsurface of the heat-dissipation section of the housing.

In another aspect of the present invention, the fluid-circulation meansis an impeller, which is submerged within the heat-conducting fluid.

In another aspect of the present invention, the Heat Removal Devicefurther includes a fluid-circulation means (FCM) for circulating theheat-conducting fluid through the fluid-flow-passage.

In another aspect of the present invention, the fluid-circulation meansis an impeller, which is located between the first and second open endsof the fluid-flow-passage.

In another aspect of the present invention, the impeller draws theheat-conducting fluid (HCF) into its second open end and impels itthrough the first open end against the internal-surface of theheat-absorbing section.

In another aspect of the present invention, the impeller impels theheat-conducting fluid (HCF) at a generally perpendicular orientationagainst the internal-surface of the heat-absorbing section.

In another aspect of the present invention, the impeller draws theheat-conducting fluid (HCF) into its first open end and expels itthrough the second open end.

In another aspect of the present invention, the Heat Removal Devicefurther includes a rotating-movement-generating device (RMGD) which hasa rotating element, which is rotationally coupled to the impeller.

In another aspect of the present invention, the RMGD is located outsidethe housing and the rotational-coupling is effected by a shaft which isconnected through the housing at its first end to the rotating elementand at its second end to the impeller.

In another aspect of the present invention, the RMGD is located outsidethe housing and the rotating element and the impeller are magnets andthe rotational-coupling is effected by a magnetic force connecting therotating element to the impeller.

In another aspect of the present invention, the rotating element is anelectromagnet.

In another aspect of the present invention, the external surface of theheat-dissipation section has heat-transfer fins.

In another aspect of the present invention, the internal surface of theheat-dissipation section is heat-transfer enhanced.

In another aspect of the present invention, the internal surface of theheat-dissipation section has heat-transfer fins.

In another aspect of the present invention, the internal surface of theheat-absorption section is heat-transfer enhanced.

In another aspect of the present invention, the internal surface of theheat-absorption section has heat-transfer fins. In another aspect of thepresent invention, the heat-conducting fluid comprises water.

In another aspect of the present invention, the heat-conducting fluidcomprises ethylene-glycol.

In another aspect of the present invention, the Heat Removal Devicefurther includes a rotating-magnetic field-generating device (RMFGD)which has a rotating magnetic field, which is magnetically coupled tothe impeller.

In another aspect of the present invention, heat is transferred from theexternal surface of the heat-dissipation section to the externalenvironment by natural convection.

In another aspect of the present invention, heat is transferred from theexternal surface of the heat-dissipation section to the externalenvironment by forced convection.

In another aspect of the present invention, the heat-conducting fluidundergoes a thermodynamic phase. In another aspect of the presentinvention, the heat-conducting fluid stays in the same thermodynamicphase.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a cross-sectional elevation-view representation of the HeatRemoval Device of the present invention as used to remove heat from theCPU of a computer.

FIG. 1 b is a sectional plan-view representation of the Heat RemovalDevice of FIG. 1 a.

FIG. 2 is a cross-sectional elevation-view representation of anotherembodiment of the Heat Removal Device of the present invention, whichuses a direct-driven impeller.

FIG. 3 is a cross-sectional elevation-view representation of anotherembodiment of the Heat Removal Device of the present invention whichuses a magnetic field generating device to rotate the impeller shown inFIG. 1 a.

FIG. 4 is a cross-sectional elevation-view representation of anotherembodiment of the Heat Removal Device of the present invention, whichhas a flattened or pancake elevational profile.

DESCRIPTION OF THE INVENTION

The present invention is directed to a Heat-Removal Device, whichcombines conductive and convective heat-transfer in a simple andinexpensive design to rapidly transfer large amounts of heat from asmall area or a point source to the external environment.

Referring to FIGS. 1 a and 1 b, Heat Removal Device 12 comprises aclosed housing 12 h, which contains a cooling fluid, and a cooling-aircirculation fan 15. The cold and hot states of the cooling fluid arerepresented as 14 c and 14 h in FIGS. 1 a and 1 b. In one embodiment ofthe invention shown in FIG. 1 a, housing 12 h is configured as a chamberwhich comprises a first end-closure floor member 12 c, a secondend-closure roof member 12 p, and an intermediate vertical walled hollowmember 12 w, to define a closed, internal, hollow space 12 v. As shownin FIGS. 1 a and 1 b, vertical member 12 w is configured from a shortpiece of extruded, circular cross-sectioned tube made of a metal, suchas aluminum or copper or aluminum plated with copper or other suchheat-conductive material. Other design refinements could include platingthe inside of an extruded aluminum tube with a non-corroding,highly-conductive surface such as copper, silver, gold, diamond, orother suitable highly conductive non-corroding material to provide highheat-transfer at an economical price.

To dissipate heat efficiently, a plurality of fins 12 f is provided onthe exterior surface of vertical member 12 w. Such fins can also beprovided on the exterior surface of roof member 12 p if additionalheat-transfer area is desired. While only 12 fins have been shown inFIG. 1 b, it will be obvious that the maximum possible number of finsthat can be physically accommodated on the external surface of verticalmember 12 w will be advantageous to provide the maximum heat-dissipationfrom vertical member 12 w. Vertical member 12 w and roof member 12 ptherefore comprise the heat-dissipation section of Heat Removal Device12.

Located within internal volume 12 v is a volume displacement member(VDM) 12 s, which is configured as a short length of a thick-walled tubemade of Styrofoam or other such material. VDM 12 s has an outsidediameter which is less than the inside diameter of vertical member 12 wto provide an annular flow passage 12 a between the outside diameter ofVDM 12 s and the inside diameter of vertical member 12 w. While a thickwalled tube is shown, VDM 12 s could also be fabricated of a thin-walledtube depending on the required dimensions for housing 12 h. Also VDM 12s has a vertical length that is less than the vertical length ofvertical member 12 w. The outside diameter and vertical length of VDM 12s are chosen to provide a top flow passage 12 t which is connected to anouter annular flow passage 12 a which in turn is connected to a bottomflow passage 12 b. It will be obvious to one of ordinary skill in theart that these flow-passages have to have adequate dimensions to allowthe cooling fluid to flow there-through without excessive pressure drop.The dimensions are also selected to provide an optimum heat-transfercoefficient between the liquid and the internal wall of vertical member12 w. The optimum value of these dimensions can be chosen throughtheoretical calculations, or experimental trial-and-error, orcomputer-aided computational fluid dynamic calculations. Such methodsare considered to be within the knowledge base of one of ordinary skillin the art.

Further VDM 12 s has an inside diameter, which is chosen to accommodatea fluid-circulation means (FCM), such as cooling-fluid pump impeller 16i, described below, therein. The inside diameter of VDM 12 s is alsochosen to provide a concentric, circular fluid flow-passage 12 cfconnecting upper flow channel 12 t to lower flow channel 12 b. It willbe obvious that fluid flow-passage 12 cf has to have a suitable diameterto allow the cooling fluid to flow there-through without excessivepressure drop while providing an optimum impinging jet on floor 12 c totransfer heat away from the hot surface.

Thus the placement of VDM 12 s within internal volume 12 v creates atoroidal flow-path for the cooling fluid within housing 12 h. In thisflow-path, the cooling fluid is impelled downwards through the centralflow passage 12 cf and impinges the internal surface 12 ci of floor 12c, and is then deflected outwards radially into lower flow passage 12 btowards the internal surface 12 wi of vertical member 12 w. It will beobvious that some stand-off means (not shown for clarity), such as legsor supports, for raising VDM 12 s away from bottom floor plate 12 cneeds to be provided to create the lower flow passage 12 b. The coolingfluid then passes upwards within annular flow passage 12a and thenradially inwards in top flow passage 12 t from where it is inducted intocentral flow passage 12 cf by the suction action of impeller 16 i.

During operation of Heat Removal Device 12, cooling air fan 15 isactivated to create forced convection by blowing cold cooling air 15 cthrough flow channels 12 fc between adjacent fins 12 f of verticalmember 12 w. While not shown, flow directing means, such as a cowl, canbe provided around the periphery of fan 15 to direct the maximum amountof air over fins 12 f. The cooling-air fan has blades 15 b, which areconnected to a rotating movement generating device, such as electricmotor 15 z. In FIG. 1 a, blades 15 b are shown connected to rotatingshaft 15 s of motor 15 z. At its free end, shaft 15 s is also connectedto a magnetic coupling member 15 m. Magnetic coupling member 15 m islocated so that its magnetic surface can rotate freely over the uppersurface of top plate 12 p of housing 12 h. Ideally, to reduce friction,a small gap is provided between the magnetic surface of magneticcoupling member 15 m and the upper surface of top plate 12 p of housing12 h. As will be described below, magnetic coupling 15 mnon-contactingly rotates cooling fluid impeller 16 i.

During operation of Heat Removal Device 12, the heat, (represented by“Q” in FIG. 1 a), generated by the hot-surface is transferred to thecold cooling fluid 14 c through its contact with internal surface 12 ciof heat-conductive floor plate 12 c of housing 12 h. Heat-conductivefloor plate 12 c therefore comprises the heat-absorption section of HeatRemoval Device 12. The heated cooling fluid 14 h then passes upwardsthrough annular flow channel 12 a and transfers its heat through itscontact with cooler internal surface 12 wi of vertical wall 12 w. Theheat is then conducted away from wall 12 w by fins 12 f, which transferthe heat to the ambient air of the external environment, either bynatural or forced convection. If cooling-air fan 15 is in operation, thecold air 15 c absorbs the heat from hot fins 12 f by forced convection,as shown in FIG. 1 a. If cooling-air fan 15 is not in operation, theambient air surrounding hot fins 12 f absorbs the heat from hot fins 12f by natural convection, as shown in FIG. 3. The cooled cooling fluid 14c is then recirculated back to central fluid flow passage 12 cf forremoving additional heat from the hot surface as previously described.

To rotate impeller 16 i, a magnetic coupling 16 m is provided withinvolume 12 v. Magnetic coupling 16 m is attached to impeller 16 i byshaft 16 s. While a fan-propeller type of impeller is shown, otherimpeller forms such as an Archimedes Screw can also be used to move thecooling fluid. Coupling 16 m is non-contactingly coupled to matingmagnetic coupling 15 m, which was described above. Thus the rotationalmotion of external mating magnetic coupling 15 m is non-contactinglytransferred to internal mating magnetic coupling 16 m by magnetic forcesthat pass through roof member 12 p. This arrangement provides ahermetically sealed housing 12 h and prevents leakage of the coolingfluid.

Roof member 12 p is plastic or non-ferrous metal or other material,which will not substantially obstruct the magnetic force linkage betweencoupling members 15 m and 16 m.

While impeller 16 i is shown as magnetically driven by cooling fan motor15 z, it could also be direct coupled to shaft 15 s of motor 15 z, asshown in FIG. 2. In this situation, a liquid-tight shaft-seal (notshown) will be needed in roof member 12 p for the through-insertion ofshaft 15 s into central flow passage 12 cf to attach to impeller 16 i.Alternatively, impeller 16 i can be rotated by its own dedicated,hermetically sealed motor that is located within housing 12 h. Thededicated motor could be connected to the external electrical powersource by wires that penetrate housing 12 h in a liquid-tight manner.All of these modifications for rotating impeller 16 i will be obvious toone of ordinary skill in the art and are considered to fall within thescope of the present invention.

The cooling fluid 14 c can be a gas such as Freon or it can be a liquidsuch as water or ethylene-glycol, or other such liquid. Any other fluidor mixture of fluids that can meet the required heat-transfer,non-corrosiveness, non-toxicity, and other desired characteristics ofthe application can also be used. Further, the fluid may or may notundergo a thermodynamic phase-change. Yet other configurations andmodification of Heat Removal Device 12 disclosed herein will be obviousto persons skilled in the art. These configurations are considered tofall within the scope of the present invention.

While the above disclosure relates to the use of the Heat Removal Deviceof the present invention for cooling ICs, it could also have otherapplications for removal of spot heat. For example, it could be used forcooling bearings or other machine parts.

Yet further refinements can be provided to enhance the performance ofHeat Removal Device 12 of the present invention.

For example, liquid flow straighteners can be used to maintain thetoroidal flow-path within housing 12 h and thereby enhance the pumpingefficiency of impeller 16 i.

Further, housing 12 h may have other cross-sections besides the circularcross-section shown in FIG. 1 b. Vertical section 12 w of housing 12 hcould take on other geometric or non-geometric shapes. For example, thevertical section 12 w could be hexagonal and the fins could create asquare profile if desired.

Yet further, as shown in FIG. 1 a, heat-transfer enhanced surfaces 12 ceon internal surface 12 ci of bottom plate 12 b and 12 we on internalsurface 12 wi of vertical member 12 w can be provided to increase theheat-transfer from the hot surface to the cooling fluid and cooling air.Such means to enhance the heat-transfer from between a surface and afluid includes dimples, etchings, grooves, fins, pins or any other meansof disturbing the laminar flow boundary of the fluid to create turbulentflow, which is known to enhance heat-transfer. Such an enhancedheat-transfer surface can be provided on the internal side of floorplate 12 c, where floor plate 12 c contacts the hot surface, to increaseheat-transfer from floor plate 12 c to cooling fluid 14 c.

Similar, heat-transfer enhancement means 12 we can be provided on theinternal side of vertical section 12 w, opposite the location of fins 12f, to enhance heat-transfer from hot cooling-fluid 14 h to fins 12 f.

Yet further, additional means of creating and maintaining turbulent flowof cooling-fluid 14 c to enhance heat transfer can be provided. Forexample, the internal wall of vertical section 12 w or the surfaces ofinternal fluid displacer 12 s can be roughened to create turbulent flow.Alternately, protrusions can be provided on these surfaces to createturbulent flow in cooling-fluid 14 c.

Similarly, the heat-transferring surfaces of fins 12 f could beroughened by methods such as sand-blasting or other such processes, tocreate a turbulent flow of cold air 15 c over fins 12 f to enhance heattransfer. All such heat-transfer enhanced surfaces are considered tofall within the scope of the present invention.

While the preferred embodiment of the invention has been shown anddescribed with the internal volume displacement device 12 s, there couldbe other means of creating largely toroidal flow to achievesubstantially the same results. All such means of creating toroidal floware considered to fall within the spirit of this invention. Theinvention may even be practiced without volume displacement means 12 sas it is highly likely that even random or uncontrolled flow patternpumping of cooling-fluid 14 c within housing 12 h would produce at leastsome of the heat-transfer effects described above.

In the preferred embodiment, the toroidal flow is directed throughcentral fluid flow passage 12 cf of VDM 12 s to impinge on internalsurface 12 ci of Heat Removal Device 12. However, in another embodimentof the present invention shown in FIG. 2, the flow is reversed withcooling fluid 14 c moving upwards in central flow passage 12 cf, awayfrom heated absorption section 12 c. As shown in FIG. 2, to maintain thecounter-current flow between the cooling fluid 14 c and the cooling air15 c, the rotation of cooling air fan blades 15 b can also be reversed.Alternately, though less efficient from a heat-transfer point of view, aco-current flow can be maintained between cooling fluid 14 c and coolingair 15 c.

In the description of the Heat Removal Device of the present invention,a propeller type pump is depicted. However, other arrangements may alsobe conceived to incorporate other types of pumps such as centrifugalpumps, mixed flow pumps, etc. It is also not necessary that the pump belocated in central flow passage 12 cf. The pump could be locatedanywhere in the fluid circulation flow-path to circulate the fluid pastthe heat-absorption and heat-dissipation sections. A further refinementto the design would be a nozzle, which could be fitted to the bottomflow-opening 12 cx of fluid flow-passage 12 cf to enhance theimpingement of cooling fluid 14 c on floor plate section 12 c of HeatRemoval Device 12.

The pump, pump housing, magnetic drive and bearings may be manufacturedas a complete sub-assembly that will easily be fitted into VDM 12 s. Forexample, for lower cost and ease of assembly, a centrifugal pump with anintegrated magnetic coupling could be provided in upper flow opening 12cy.

Yet other modifications can be made to Heat Removal Device 12 of thepresent invention to suit specific applications. For example, thevertical height of Heat Removal Device 12 could be shortened to suitheadroom constraints, such as in laptop computers. Thus, in this designrepresented by FIG. 4, Heat Removal Device 12 would have a flattened orpancake elevational profile. The location and orientation of fins 12 fcan also be adjusted to fit specific design constraints. All of thesemodifications are considered to fall within the scope of the presentinvention.

Yet further, as shown in FIG. 3, magnetic coupling 16 m could be rotatedby a rotating magnetic field generating device 15 zm, which wouldinclude a plurality of stationary electromagnetic poles 15 zp. Forexample, a stator of an electric motor could be used to create arotating magnetic field to rotate magnetic coupling 16 m.

Further, as shown in FIG. 4, impeller 16 im could itself be magnetizedto eliminate the magnetic coupling member and connecting shaft. Thusimpeller 16 im would be directly magnetically coupled to the rotatingmagnetic field created by rotating magnetic field generating device 15zm.

Further, the heat recovery device of the present invention can be usedwith more than one heat-source. For example, FIG. 4 shows the pancakeversion of Heat Removal Device 12 being used with a plurality of LiquidCrystal Display (LCD) elements. Heat Removal Device 12 can also usedwith a plurality of Light Emitting Diode (LED) elements.

All of these design alternatives and refinements are considered to fallwithin the scope of the present invention, which should be limited, onlyby the scope of the following claims.

1) A device for removing heat from a hot-surface, the device comprising:a generally closed chamber, the chamber having a first end-closuremember, a second end-closure member, and an intermediate-memberconnecting the first end-closure member to the second end-closuremember, the first end-closure member having a heat-absorbing section,the heat-absorbing section having an external surface in contact withthe hot-surface and an internal surface, the second end-closure memberand intermediate-member together or individually functioning as aheat-dissipation section which is exposed to the external environment;and a heat-conducting fluid located within the chamber, theheat-conducting fluid generally contacting both the internal surface ofthe heat-absorbing section and the internal surface of theheat-dissipation section. 2) The device of claim 1, further including afluid-circulation means for circulating the heat-conducting fluid pastthe internal surface of the heat-absorbing section and the internalsurface of the heat-dissipation section of the chamber. 3) The device ofclaim 1, further including an open fluid-flow-passage having a firstopen end submerged in the heat-conducting fluid adjacent to the internalsurface of the heat-absorbing section of the chamber and having a secondopen end submerged in the heat-conducting fluid adjacent to the internalsurface of the heat-dissipation of the chamber. 4) The device of claim2, wherein the fluid-circulation means is an impeller, which issubmerged within the heat-conducting fluid. 5) The device of claim 3,further including a fluid-circulation means for circulating theheat-conducting fluid through the fluid-flow-passage. 6) The device ofclaim 5, wherein the fluid-circulation means is an impeller which islocated between the first and second open ends of thefluid-flow-passage. 7) The device of claim 6, wherein the impeller drawsthe heat-conducting fluid into its second open end and impels it throughthe first open end against the internal-surface of the heat-absorbingsection. 8) The device of claim 7, wherein the impeller impels theheat-conducting fluid at a generally perpendicular orientation againstthe internal-surface of the heat-absorbing section. 9) The device ofclaim 6, wherein the impeller draws the heat-conducting fluid into itsfirst open end and expels it through the second open end. 10) The deviceof claim 6, further comprising a rotating-movement generating devicewhich has a rotating element which is rotationally-coupled to theimpeller. 11) The device of claim 10, wherein the rotating-movementgenerating device is located outside the chamber and therotational-coupling is effected by a shaft which is connected throughthe chamber-wall at its first end to the rotating element and at itssecond end to the impeller. 12) The device of claim 10, wherein therotating-movement generating device is located outside the chamber andthe rotating element and the impeller are magnets and therotational-coupling is effected by a magnetic force connecting therotating element to the impeller. 13) The device of claim 12, whereinthe rotating element is an electromagnet. 14) The device of claim 1,wherein the external surface of the heat-dissipation section hasheat-transfer fins. 15) The device of claim 1, wherein the internalsurface of the heat-dissipation section is heat-transfer enhanced. 16)The device of claim 1, wherein the internal surface of theheat-dissipation section has heat-transfer fins. 17) The device of claim1, wherein the internal surface of the heat-absorption section isheat-transfer enhanced. 18) The device of claim 1, wherein the internalsurface of the heat-absorption section has heat-transfer fins. 19) Thedevice of claim 1, wherein the heat-conducting fluid comprises water.20) The device of claim 1, wherein the heat-conducting fluid comprisesethylene-glycol. 21) The device of claim 6, further comprising arotating-magnetic field generating device which has a rotating magneticfield which is magnetically-coupled to the impeller. 22) The device ofclaim 1, wherein heat is transferred from the external surface of theheat-dissipation section to the external environment by naturalconvection. 23) The device of claim 1, wherein heat is transferred fromthe external surface of the heat-dissipation section to the externalenvironment by forced convection. 24) The device of claim 1, wherein theheat-conducting fluid undergoes a thermodynamic phase-change. 25) Thedevice of claim 1, wherein the heat-conducting fluid stays in the samethermodynamic phase 26) A device for removing heat from a hot-surface,the device comprising: a generally closed housing, the housing having aheat-absorbing section and a heat-dissipation section, theheat-absorbing section having an external surface in contact with thehot-surface and an internal surface, the heat-dissipation section havingan external surface which is exposed to the external environment and aninternal surface; and a heat-conducting fluid located within thehousing, the heat-conducting fluid generally contacting both theinternal surface of the heat-absorbing section and the internal surfaceof the heat-dissipation section. 27) A device for removing heat from ahot-surface, the device comprising: a generally closed liquid-filledchamber, a first external surface of which is in contact with thehot-surface to receive heat therefrom, a second external surface ofwhich is exposed to the external environment to transfer heat thereto.